joregelt2 wrote:what you say is probably true, but I think it would be unlikely that youtube or another streaming media site, would cap their bandwidth per stream to less than is required to view their own content. Don't you agree that this would be a little counterintuitive??
The internet is a complex thing. I'm not saying that Youtube have a configuration option on their server saying "limit streams to 300Kbps". The routing path that the traffic is travelling may go through numerous hops that are bottlenecked in speed or subject to QoS protocols. The resulting nature that you see are speed limited individual streams. This phenomenom has existed on the internet for a long time; it is the premise on which download accelerators are marketed (they break a single file down into multiple parts and make each part download individually, then amalgamate the result).
joregelt2 wrote:I do not understand why 3.5 Mbps when sync is 16 Mbps is considered adequate.
That is just the convention that ADSL providers have been set by the telecommunication ombudsman (i.e. anything >1.5Mbps is "adequate" regardless of technicalities. Your circumstances are an unfortunate byproduct of this.
joregelt2 wrote:Exetels mirror should be able to send me data much faster than that, if it just me <---> exetel, and not influenced by general "congestion".
My understanding of congestion is that it exists at multiple levels in any network. Your individual connection / sync speed of 16Mbps is only one of these levels. Your exchange may be linked to a high number of heavy ADSL users causing congestion at the exchange level. The local Exetel network through which the mirror is connected may experience congestion. Out beyond the Exetel mirror you have the wider Optus/Powertel infrastructure, the national infrastructure, the individual cables on the sea bed connecting Australia with the world, etc. Many areas for congestion to arise, in mirrors and international sites
joregelt2 wrote:I think that I am entitled to be a little concerned and unsatisfied if my adsl2+ connection that syncs at 16 Mbps can only transfer data at 200 kbps. This is almost not enough for VOIP, and certainly not enough for VOIP + surfing.
Your 200kbps speeds are based solely on Youtube. You are getting 3.5Mbps average speeds in real-world traffic. This is the performance you should be basing your conclusions on, which is sufficient enough for VOIP and surfing.